diff --git a/Dashboard.Common/Measure.cs b/Dashboard.Common/Measure.cs
new file mode 100644
index 0000000..61fbf8d
--- /dev/null
+++ b/Dashboard.Common/Measure.cs
@@ -0,0 +1,86 @@
+namespace Dashboard
+{
+    public enum MeasurementUnit
+    {
+        /// <summary>
+        /// The default unit. A size of a single picture element.
+        /// </summary>
+        Pixel,
+        /// <summary>
+        /// 1/72th of an inch traditional in graphics design.
+        /// </summary>
+        Point,
+        /// <summary>
+        /// The universal length unit for small distances.
+        /// </summary>
+        Millimeter,
+        /// <summary>
+        /// An inverse proportional unit with respect to the container size.
+        /// </summary>
+        Star,
+        /// <summary>
+        /// A directly proportional unit with respect to the container size.
+        /// </summary>
+        Percent,
+    }
+
+    public record struct AdvancedMetric(MeasurementUnit Unit, float Value)
+    {
+        public AdvancedMetric Convert(MeasurementUnit target, float dpi, float rel, int stars)
+        {
+            if (Unit == target)
+                return this;
+
+            float pixels = Unit switch {
+                MeasurementUnit.Pixel => Value,
+                MeasurementUnit.Point => Value * (72f / dpi),
+                MeasurementUnit.Millimeter => Value * (28.3464566929f / dpi),
+                MeasurementUnit.Star => Value * rel / stars,
+                MeasurementUnit.Percent => Value * rel / 100,
+                _ => throw new Exception(),
+            };
+
+            float value = target switch {
+                MeasurementUnit.Pixel => pixels,
+                MeasurementUnit.Point => Value * (dpi / 72f),
+                // MeasurementUnit.Millimeter =>
+            };
+
+            return new AdvancedMetric(target, value);
+        }
+
+        public override string ToString()
+        {
+            return $"{Value} {Unit.ToShortString()}";
+        }
+
+        public static bool TryParse(ReadOnlySpan<char> str, out AdvancedMetric metric)
+        {
+            metric = default;
+            return false;
+        }
+
+        public static AdvancedMetric Parse(ReadOnlySpan<char> str) =>
+            TryParse(str, out AdvancedMetric metric)
+                ? metric
+                : throw new Exception($"Could not parse the value '{str}'.");
+    }
+
+    public static class MeasurementExtensions
+    {
+        public static bool IsRelative(this MeasurementUnit unit) => unit switch {
+            MeasurementUnit.Star or MeasurementUnit.Percent => true,
+            _ => false,
+        };
+        public static bool IsAbsolute(this MeasurementUnit unit) => !IsRelative(unit);
+
+        public static string ToShortString(this MeasurementUnit unit) => unit switch {
+            MeasurementUnit.Pixel => "px",
+            MeasurementUnit.Point => "pt",
+            MeasurementUnit.Millimeter => "mm",
+            MeasurementUnit.Star => "*",
+            MeasurementUnit.Percent => "%",
+            _ => throw new Exception("Unknown unit."),
+        };
+    }
+}
diff --git a/Dashboard/Application.cs b/Dashboard/Application.cs
index c9c1bd0..62db7dc 100644
--- a/Dashboard/Application.cs
+++ b/Dashboard/Application.cs
@@ -67,6 +67,7 @@ namespace Dashboard
         public virtual void Leave()
         {
             Backend.Leave();
+            Leaving?.Invoke(this, EventArgs.Empty);
         }
 
         public void Run() => Run(true, CancellationToken.None);
diff --git a/tests/Dashboard.TestApplication/Program.cs b/tests/Dashboard.TestApplication/Program.cs
index 17a80ea..1b174b9 100644
--- a/tests/Dashboard.TestApplication/Program.cs
+++ b/tests/Dashboard.TestApplication/Program.cs
@@ -4,7 +4,6 @@ using System.Text;
 using Dashboard.Drawing.OpenGL;
 using Dashboard.ImmediateUI;
 using Dashboard.OpenTK.PAL2;
-using OpenTK.Graphics;
 using OpenTK.Platform;
 using OpenTK.Graphics.OpenGL;
 using OpenTK.Mathematics;